The main objective is to determine how the speech of the deaf differs from that of the normal hearing. The acoustic, articulatory, and perceptual characteristics of both deaf and normal speech will be examined for systematic differences. Both segmental and suprasegmental errors in the speech of the deaf will be determined and their mutual effect on intelligibility evaluated. Acoustic analyses will be carried out on both deaf and normal speech to determine which acoustic parameters are most directly affected by these errors. The acoustic analysis will be mainly by digital computer using digital techniques for determining the power spectrum, formant frequencies and bandwidths, fundamental frequencies, and short-term energy. The characteristics common to deaf speakers will be separated from those idiosyncratic speech characteristics of individual speakers and from those of distinct subgroups of the population.